Biochemical and physiological parameters and estimated work output in draught horses pulling loads for long periods.

This study explores how continuous heavy load pulling affects the cardiovascular, respiratory, and metabolic health of horses. It found that horses can adapt to pulling heavy loads across multiple days, with physiological markers indicating improved fitness over time.

Research Methods and Parameters

• The study involved five draught horses, with an average body weight of 648 +/- 33 kg, pulling loads continuously.
• A specially equipped cart fitted with an odometer and hydraulic dynamometer was used to measure the distance traveled and the force exerted by the horse respectively.
• The physiological parameters monitored included heart and respiration rates and rectal temperatures. Blood samples were collected to measure various biochemical parameters like arterial and venous pH, blood gases, glucose and lactic acid levels, and the activity of certain enzymes.
• The work schedule consisted of 8-hour workdays for five consecutive days, with a ten-minute rest each hour.

Significant Findings

• The horses were able to tolerate the draught exercise well, as evidenced by their recovery from the changes observed during the work.
• At the beginning of the work period, there were notable increases in the serum activity of muscle-derived enzymes and in blood lactate concentrations – clear signs of fitness loss. But as the horses continued to work across the following days, they adapted and these levels reduced significantly.
• This adaptation process is similar to the one observed in racehorses, suggesting that serum activities of muscle-derived enzymes, like creatine phosphokinase (CK), alongside blood lactate concentrations could serve as good fitness indicators in draught horses.

Implications of the Research

• This study provides valuable insights into the physiological and biochemical impacts of continuous load pulling on horses, a common practice in farming and other industries.
• The findings suggest that horses can adapt to sustained periods of heavy work, which has implications for work scheduling and perhaps even horse breeding programs.
• It also highlights potential fitness monitoring indicators like blood lactate concentrations and CK activity, which can assist in the health and wellbeing of draught horses.